Synthesis Of Thiourea Derivatives And Heterocyclic Compounds In Ionic Liquid

Ionic liquids have recently attracted much attention as environment friendly media for organic reactions. In contrast to traditional organic solvents, they exhibit obvious advantageous properties including wide liquid range, good thermal and chemical stability, high ionic conductivity, negligible vapor pressure and potential for recycling. Because of these properties, ionic liquids emerge as a new green alternative to traditional organic solvents in the applications of organic synthesis.Thiourea and its derivatives have been found their ways into almost every branch of chemistry. Commercially, they are used in dyes, photographic film, elastomers, plastics and andtextiles. Certain thiourea derivatives are insecticides, preservatives, rodenticides, and Pharmaceuticals. In the academic field thioureas are of great value in the characterization of organic compounds.This thesis has been utilized ionic liquids as solvents for synthesis of thiazolon-4-ones, thioureas and its derivatives acyl thioureas. The thesis mainly includes two parts:The part of the review introduces the development, composition, preparation and application of ionic liquids.The other part of the experiment includes three sections: (1) The thioureas are synthesized in ionic liquid [bmim][SCN] via its reaction with halides and amines. In the process of the reactions, the ionic liquids not only act as solvent but also reactant. The reactions are found to proceed under relative mild conditions. It is a efficient, time-saving and environment friendly method. (2) Acyl thioureas are synthesized using acyl chlorides, NH4SCN and amines in several kinds of ionic liquids. It is found that the reactions in [bmim][BF₄] get the best result with the advantage of short reaction time and high yields. It is also found that ionic liquid can be recycled and reused effectively. This provides a new, effective method to synthesize acyl thioureas. (3) Thiazolon-4-ones are prepared by using ionic liquids [bmim] [SCN] as solvent and reactant. The reactions of [bmim][SCN] with ethyl 2-chloroacetate and amines is rapid and easy. The yields are about 73%. It provides a new method to synthesize the thiazolon-4-ones.